Can Hand Sanitiser Affect a Drink Driving Breathalyser Test?

How Drink Driving Breathalyser Tests Work in the UK

Drink driving investigations in England and Wales usually begin with a roadside breath test.

Police officers use a handheld device to measure the amount of alcohol in a person’s breath. If the result indicates alcohol above the legal limit, the driver may be arrested and taken to a police station for further testing.

At the police station, an evidential breathalyser is used to measure alcohol concentration more accurately.

The current legal limit in England and Wales is: 

• 35 micrograms of alcohol per 100 millilitres of breath 

This limit is set out in the Road Traffic Act 1988, which governs drink driving offences. 

Evidence from evidential breath testing may be used in court to support a charge of driving with excess alcohol.

Why Hand Sanitiser Can Affect Breathalyser Readings

Alcohol-based hand sanitisers typically contain a high concentration of ethanol.

When sanitiser is applied to the hands, it evaporates quickly. This releases alcohol vapour into the surrounding air.

Because breathalysers are designed to detect alcohol molecules, these vapours may sometimes be detected by the device.

Contamination can occur in several ways;

Alcohol vapour near the device

If sanitiser is used immediately before testing, alcohol vapour may still be present in the air around the breathalyser.

Contamination of the mouthpiece

If sanitiser residue is transferred to the mouthpiece, the device may detect alcohol that was not actually consumed.

Sanitiser used by the test operator

Studies have shown that alcohol vapour from sanitiser used by the person administering the test can influence readings in certain circumstances.

For this reason, breath testing procedures are designed to reduce the risk of contamination.

When Breathalyser Results May Be Challenged

Breathalyser evidence is often central to drink driving prosecutions. However, the reliability of the test result may be questioned in certain circumstances. 

Examples may include: 

• Improper testing procedure 
• Equipment malfunction 
• Contamination of the device 
• Environmental alcohol vapour 
• Medical or physiological factors 

If a breath test result appears unusually high or inconsistent with the circumstances, further investigation may be needed.

In some cases, expert evidence relating to breath testing procedure or scientific reliability may be relevant to the defence.

Police Procedure for Drink Driving Breath Tests

Police officers must follow specific procedures when carrying out breath tests. 

These procedures are designed to ensure that the result is reliable and can be used in court.

Typical safeguards include: 

• Using a new sterile mouthpiece 
• Ensuring the device is properly calibrated 
• Conducting two evidential breath tests 
• Following correct waiting periods before testing 

Failure to follow proper procedure may affect the reliability of the evidence.

What To Do If You Believe Your Breath Test Was Inaccurate

If you are investigated or charged with drink driving, legal advice should be sought as soon as possible.

A solicitor experienced in motoring offences can examine: 

• The breath testing procedure used 
• Calibration records for the equipment 
• Custody records and police notes 
• Possible contamination issues 

Early legal advice can help assess the evidence and identify any issues with the breath test procedure.

Speak to a Drink Driving Defence Solicitor

Drink driving allegations can carry serious consequences, including disqualification from driving, fines and a criminal conviction. 

If you are facing a drink driving investigation or charge, a criminal defence solicitor can help you understand your legal position and the options available.

Specialist legal advice may be particularly important where there are concerns about the reliability of breath test evidence.